The present invention relates to electro-optical display devices in which a material whose optical aspect changes under the action of an electrical voltage is disposed in a thin layer between two electrodes. By applying between the two electrodes an electrical voltage, the material changes in aspect at the crossing point of these two electrodes. In the case where matrix selection is used with a material having a threshold effect, the voltages applied to the other electrodes are such that at the crossing point between these two electrodes and the two electrodes selected for visualizing the chosen dot, the potential difference is less than the threshold voltage. Thus only the selected crossing point changes in optical aspect.
Such an addressing device is described in particular in the work entitled "Opto-electronique" by G. Broussaud bearing the reference ISBN: 2-225 3918-6, pages 208 to 210. There will be found in this same work, as an example of a threshold-effect material, nematic liquid crystals operating in the twisted mode and called twisted nematic; see pages 298 to 300.
However in such a twisted nematic crystal device the inscription speed and the contrast are relatively moderate and moreover this device does not comprise an internal memory, which requires a permanent dynamic inscription using the retinal assistance but reduces the maximum possible resolution.